To make the marinade, grab a small separate bowl and whisk together brown sugar, soy sauce, orange juice, orange zest, olive oil, paprika, garlic powder, and cracked pepper. Whisk together to combine.
Place chicken breasts in a large ziplock bag and set the bag inside a mixing bowl to sit upright. Pour the marinade over the chicken. Seal and give a gentle squeeze or two to coat the chicken all over with the marinade in the bag.
Marinade chicken breasts in the large ziplock bag for 30 minutes to an hour, or overnight in the refrigerator, turning and re-coating the meat occasionally.
If marinating and cooking the same day, marinade at room temperature for optimal flavor, then cook.
Turn the grill on, pre-heat, and grease your grill grate with a generous layer of non-stick cooking spray, so the marinated chicken does not stick.
Grill marinated chicken breasts over medium heat for 5 (to 7 ) minutes per side depending on the size and thickness of the chicken breasts. You can also cook through until an internal temperature of 165 degrees F is reached.
When cook time is up, remove chicken breast from grill and transfer to a serving platter. Cover loosely with a bit of foil and let the chicken breasts rest for another 5 minutes. Slice and serve.